Wood the material of choice at schools

The government is promoting a shift from reinforced concrete to wood for school buildings because of the favorable educational and health effects.

“Surrounded by wood, I feel comfortable and can improve my concentration,” said Riku Kubota, a 12-year-old sixth-grader at Itako Elementary School, a municipal school in Itako, Ibaraki Prefecture. The school was rebuilt with wood last April.

Wooden structures accounted for 20 percent of buildings or gymnasiums at public kindergartens, elementary schools, junior high and high schools, and special schools newly built or renovated in fiscal 2012, up 5 percentage points from the previous year, the education ministry said.

In addition, about half of concrete buildings have had wooden floors and walls installed.

Wood was used to build schools in prewar Japan. But most wooden school buildings were replaced with reinforced concrete structures for the sake of earthquake resistance in the postwar era through Japan’s high-growth period.

Starting in the 1980s, however, the construction of wooden schools increased as technological advances made them more quake-resistant. Increased calls for using domestic wood also contributed to the trend.

As an unexpected effect, the Japan Housing and Wood Technology Center reported that the number of classes temporarily closed due to influenza at wooden schools was less than one-third of that for concrete schools. The center conducted a one-year survey of selected schools, finding that 7 percent of classes were canceled for flu in concrete schools against 2 percent for wooden schools.

Wood is thought to prevent the spread of flu by maintaining a certain level of humidity even in winter, according to the Ministry of Education, Culture, Sports, Science and Technology.

The headmaster of the Itako school said the number of children absent due to colds seems to have decreased since the school was rebuilt.

The center’s survey also found that children made fewer visits to sick rooms after suffering injuries at school in wooden buildings. While attributing the finding to wood’s shock-absorbing nature, experts also pointed out that falls occur less frequently on wooden floors as dew condensation rarely occurs.

As wooden schools cost about 5 percent more to build than concrete ones, the ministry has increased subsidies for construction of them.

The government also plans to amend the building code to facilitate the construction of three-story wooden school buildings.